A coolant control valve may be applied to an engine system of a vehicle to control a flow amount and/or direction of a coolant for the purposes of improving fuel efficiency and output, while reducing emissions.
The coolant control valve may adjust the temperature of a coolant by circulating the coolant through a circulation flow path between a cooling jacket of the engine and a radiator, and may block the flow of the coolant toward the radiator during a cold start of the vehicle to thereby warm-up the engine. In addition, the coolant control valve may also be used for various warm-up applications by allowing the coolant to flow into an oil warmer, an exhaust-gas recirculation (EGR), a heater and the like.
Meanwhile, the coolant control valve may be provided with a fail-safety type thermostat. The thermostat may force the coolant to flow toward the radiator when the coolant control valve is stuck due to errors in a sensor signal and a control circuit, abnormal control of a driving motor and the like, thereby preventing overheating of the coolant.
The thermostat may contain a wax in the interior thereof. When the temperature of the coolant is increased to be higher than or equal to a predetermined value, the coolant control valve may forcibly be driven to force the coolant to flow toward the radiator.
However, the wax of the thermostat may be repeatedly liquefied and solidified according to changes in the temperature of the coolant, which may lead to a frequent failure of the thermostat itself. Thus, the entirety of the coolant control valve may need to be replaced, which may increase maintenance costs.
In a case in which the temperature of the coolant is increased in a section of the cold engine start, the thermostat needs to operate only when the flow path to the radiator is opened. Thus, the cost-effectiveness of the thermostat may be low.